JPWO2017043238A1 - Battery monitoring device - Google Patents

Abstract

The state of the relay provided respectively on the positive terminal side and the negative terminal side of the secondary battery is correctly detected. The positive main relay 12 conducts or cuts off between the first positive contact and the second positive contact, and the negative main relay 15 conducts between the first negative contact and the second negative contact. Or shut off. The microcomputer 2 includes a first voltage between the first positive electrode contact and the first negative electrode contact, a second voltage between the second positive electrode contact and the first negative electrode contact, and a first positive electrode. A third voltage between the contact and the second negative contact can be measured. The microcomputer 2 detects the state of the positive main relay 12 based on the voltage measurement result when the measurement of the first voltage and the measurement of the second voltage are performed in synchronization with each other. The state of the negative main relay 15 is detected based on the voltage measurement result when the voltage measurement of 3 is performed in synchronization.

Description

  The present invention relates to a battery monitoring device.

  2. Description of the Related Art Conventionally, a battery system that includes a chargeable / dischargeable secondary battery and supplies power to a device mounted on an automobile or the like is known. In such a battery system, generally, relays (contactors, relays) are provided on the positive electrode terminal side and the negative electrode terminal side of the secondary battery in order to switch the conduction state between the secondary battery and the device.

  Patent Document 1 discloses a power supply device that detects welding of contactors provided on a positive electrode terminal side and a negative electrode terminal side of a vehicle running battery, respectively. This power supply device is equipped with a simple voltage detection circuit, and by switching the switch connected to this simple voltage detection circuit, the voltage on the battery side and the output side when the contactor is controlled to be in the OFF state, respectively. taking measurement. As a result, if the voltages on the battery side and the output side match, it is determined that the contactor is welded.

JP 2008-92656 A

  In the power supply device disclosed in Patent Document 1, welding of the contactor can be detected, but this cannot be detected when the contactor is in a state where it cannot conduct. Further, a time difference corresponding to the switch switching time is generated between the voltage detection timing on the battery side and the voltage detection timing on the output side. Therefore, when voltage fluctuation occurs due to charging / discharging of the battery, even if the contactor is welded, it is determined to be normal because there is a difference between the detected voltage value on the battery side and the detected voltage value on the output side. May be. As described above, in the conventional technique, the state of the contactor may not be detected correctly.

  A battery monitoring device according to the present invention includes a voltage measuring circuit that performs voltage measurement for detecting a state of a positive side relay and a negative side relay connected between a positive electrode terminal and a negative electrode terminal of a secondary battery and a load, An interface circuit group provided between the voltage measurement circuit and the positive side relay and the negative side relay, wherein the positive side relay is provided on the positive terminal side of the secondary battery. Between the contact and the second positive electrode contact provided on the load side, the negative electrode side relay is a first negative electrode contact provided on the negative electrode terminal side of the secondary battery, The voltage measurement circuit is connected to or disconnected from a second negative electrode contact provided on the load side, and the voltage measurement circuit includes a first voltage between the first positive electrode contact and the first negative electrode contact. The second positive contact and the first positive contact A second voltage between the pole contact and a third voltage between the first positive contact and the second negative contact can be measured via the interface circuit group, and Based on the measurement result of the first voltage and the measurement result of the second voltage when the measurement of the first voltage and the measurement of the second voltage are performed in synchronization, the state of the positive-side relay is determined. Detecting, based on the measurement result of the first voltage and the measurement result of the third voltage when the measurement of the first voltage and the measurement of the third voltage are performed synchronously, the negative electrode side Detect relay status.

  ADVANTAGE OF THE INVENTION According to this invention, the state of the relay each provided in the positive electrode terminal side and negative electrode terminal side of a secondary battery can be detected correctly.

It is a figure which shows the structure of the battery system containing the battery monitoring apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the battery system containing the battery monitoring apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the battery system containing the battery monitoring apparatus which concerns on the 3rd Embodiment of this invention. It is a figure which shows the example of the control sequence at the time of normal by the 1st Embodiment of this invention, and an operation | movement expectation value. It is a figure which shows the example of the control sequence and operation expected value at the time of abnormality by the 1st Embodiment of this invention. It is a figure which shows the example of the control sequence at the time of normal by the 3rd Embodiment of this invention, and an operation | movement expectation value. It is a figure which shows the example of the control sequence and operation | movement expected value at the time of abnormality by the 3rd Embodiment of this invention.

-First embodiment-
FIG. 1 is a diagram showing a configuration of a battery system including a battery monitoring apparatus according to the first embodiment of the present invention. In the battery system shown in FIG. 1, the battery monitoring device 23 is connected to the assembled battery 11 that is a secondary battery, and monitors the assembled battery 11 by measuring the voltage of each battery cell 10 constituting the assembled battery 11. . Further, the battery monitoring device 23 detects the states of the positive-side main relay 12 and the negative-side main relay 15 provided between the assembled battery 11 and the inverter 18, and determines whether or not these are operating normally. Monitor.

  The assembled battery 11 is connected to an inverter 18 via a positive side main relay 12, a precharge relay 13 and a negative side main relay 15. The positive-side main relay 12 is provided with contacts on the positive-electrode terminal side and the inverter 18 side of the assembled battery 11, and conducts or blocks between these contacts. The negative main relay 15 is provided with contacts on the negative terminal side of the battery pack 11 and the inverter 18 side, and conducts or blocks between these contacts. Similarly to the positive main relay 12, the precharge relay 13 is provided with contacts on the positive terminal side and the inverter 18 side of the assembled battery 11, and conducts or blocks between these contacts. A precharge resistor 14 is connected in series to the precharge relay 13.

  The inverter 18 converts the DC power supplied from the assembled battery 11 into AC power and outputs the AC power to the motor 19 to drive the motor 19. At this time, the inverter 18 acts as a load of the assembled battery 11. An X capacitor 17 and Y capacitors 16 A and 16 B connected in series are connected to the assembled battery 11 in parallel with the inverter 18.

  The battery monitoring device 23 includes a power supply IC 1, a microcomputer 2, a communication interface circuit 3, insulated communication elements 4A and 4B, a cell voltage monitoring IC 5, a relay control unit 7, a current sensor interface circuit 8, a sensor connection changeover switch group 20, and a high voltage measurement. An interface circuit group 22 is included. The power supply IC 1 supplies power to the microcomputer 2 for operating the microcomputer 2. The microcomputer 2 instructs the cell voltage monitoring IC 5 to measure the voltage of each battery cell 10 of the assembled battery 11 by communicating with the cell voltage monitoring IC 5 via the communication interface circuit 3 and the insulated communication elements 4A and 4B. Then, the measurement result is obtained from the cell voltage monitoring IC 5. Further, the microcomputer 2 acquires the charge / discharge current of the assembled battery 11 measured by the current sensor 9 via the current sensor interface circuit 8. The acquisition of the charge / discharge current is preferably performed in synchronization with the acquisition of the total voltage of the assembled battery 11. Further, the microcomputer 2 detects the states of the positive main relay 12 and the negative main relay 15 by performing voltage measurement via the high voltage measurement interface circuit group 22, and determines whether these relay states are normal. Relay monitoring control for determining Details of this relay monitoring control will be described later.

  The cell voltage monitoring IC 5 measures the voltage of each battery cell 10 of the assembled battery 11 in accordance with an instruction from the microcomputer 2 and outputs the measurement result to the microcomputer 2. Based on the voltage measurement result of each battery cell 10 acquired from the cell voltage monitoring IC 5, the microcomputer 2 instructs the cell voltage monitoring IC 5 to perform cell balancing for suppressing voltage variation between the battery cells 10 as necessary. .

  The relay control unit 7 switches connection states of the positive-side main relay 12, the negative-side main relay 15, and the precharge relay 13 in accordance with instructions from the microcomputer 2. When starting the energization from the assembled battery 11 to the inverter 18, the microcomputer 2 makes the negative main relay 15 and the precharge relay 13 conductive to the relay control unit 7, and then connects the positive main relay 12 to the precharge relay 13. An instruction is given to open the charge relay 13. Thereby, charging of the X capacitor 17 is started in a state where the inrush current is limited by the precharge resistor 14 at first, and after the X capacitor 17 is sufficiently charged, power supply from the assembled battery 11 to the inverter 18 is performed. Done. Further, the microcomputer 2 performs relay control so that the positive-side main relay 12, the negative-side main relay 15 and the precharge relay 13 are all opened when there is a risk of overcharge or overdischarge in at least one battery cell 10. Instruct part 7. Thereby, the assembled battery 11 is protected from overcharge and overdischarge.

  The sensor connection changeover switch group 20 includes a plurality of switches for switching the connection state between both the contacts of the positive-side main relay 12 and both the contacts of the negative-side main relay 15 and the high-voltage measurement interface circuit group 22. The sensor connection changeover switch group 20 includes changeover switches 20A1, 20A2, 20B1, 20B2, 20C1, and 20C2. The changeover switch 20 </ b> A <b> 1 is connected between a contact (hereinafter referred to as a first negative contact) of the negative main relay 15 provided on the negative terminal side of the assembled battery 11 and the high voltage measurement interface circuit group 22. . The changeover switch 20 </ b> A <b> 2 is connected between a contact (hereinafter referred to as a first positive contact) of the positive main relay 12 provided on the positive terminal side of the assembled battery 11 and the high voltage measurement interface circuit group 22. . The changeover switch 20B1 is connected between the first negative contact and the high voltage measurement interface circuit group 22 in the same manner as the changeover switch 20A1. The changeover switch 20B2 is connected between a contact (hereinafter referred to as a second positive contact) of the positive main relay 12 provided on the inverter 18 side and the high voltage measurement interface circuit group 22. The changeover switch 20 </ b> C <b> 1 is connected between a contact (hereinafter referred to as a second negative contact) of the negative main relay 15 provided on the inverter 18 side and the high voltage measurement interface circuit group 22. The changeover switch 20C2 is connected between the first positive contact and the high voltage measurement interface circuit group 22 in the same manner as the changeover switch 20A2. Note that the switching states of the changeover switches 20A1, 20A2, 20B1, 20B2, 20C1, and 20C2 are controlled by the microcomputer 2, respectively.

  The high voltage measurement interface circuit group 22 is provided between the microcomputer 2 and the positive side main relay 12 and the negative side main relay 15. The microcomputer 2 receives the voltage between the first positive contact and the first negative contact (hereinafter referred to as the first voltage), the second positive contact and the first positive contact through the high voltage measurement interface circuit group 22. A voltage between the first negative electrode contact (hereinafter referred to as a second voltage) and a voltage between the first positive electrode contact and the second negative electrode contact (hereinafter referred to as a third voltage), respectively. It can be measured. That is, the microcomputer 2 functions as a voltage measurement circuit for measuring the first voltage, the second voltage, and the third voltage by using the high voltage measurement interface circuit group 22.

  In the present embodiment, the high voltage measurement interface circuit group 22 includes three interface circuits 22A, 22B, and 22C. The interface circuit 22A outputs the first voltage to the microcomputer 2 via the changeover switches 20A1 and 20A2. The interface circuit 22B outputs the second voltage to the microcomputer 2 via the changeover switches 20B1 and 20B2. The interface circuit 22C outputs the third voltage to the microcomputer 2 via the changeover switches 20C1 and 20C2. The interface circuits 22A, 22B, and 22C are configured by combining resistors, capacitors, and operational amplifiers, and convert the first to third voltages to voltage levels suitable for measurement by the microcomputer 2, respectively. Further, the interface circuits 22A, 22B and 22C each have a high resistance input impedance in order to ensure insulation between the high voltage circuit connected to the assembled battery 11 and the low voltage circuit including the microcomputer 2. doing.

  When the microcomputer 2 measures the first voltage via the interface circuit 22A, the microcomputer 2 switches the changeover switches 20A1 and 20A2 to the ON state and converts the first voltage output from the interface circuit 22A into a digital value. take in. When the microcomputer 2 measures the second voltage via the interface circuit 22B, the microcomputer 2 switches the changeover switches 20B1 and 20B2 to the on state and converts the second voltage output from the interface circuit 22B into a digital value. take in. When the microcomputer 2 measures the third voltage via the interface circuit 22C, the microcomputer 2 switches the changeover switches 20C1 and 20C2 to the on state and converts the third voltage output from the interface circuit 22C into a digital value. take in. The measurement result of the first voltage is used as the total voltage value of the assembled battery 11. By comparing this total voltage value with the total value of the voltage of each battery cell 10 acquired from the cell voltage monitoring IC 5, the consistency of the measurement result of the first voltage can be diagnosed.

  Based on the measurement results of the first to third voltages acquired as described above, the microcomputer 2 performs relay monitoring control. Specifically, the measurement of the first voltage and the measurement of the second voltage are performed in synchronization, and the measurement results are compared. As a result, if the first voltage and the second voltage match, it is determined that the positive-side main relay 12 is in a conducting state, and if not, the positive-side main relay 12 is in an open (cut-off) state. It is judged that. Thereby, the microcomputer 2 can detect the state of the positive-side main relay 12. In addition, the microcomputer 2 performs the measurement of the first voltage and the measurement of the third voltage in synchronization, and compares these measurement results. As a result, if the first voltage and the third voltage match, it is determined that the negative-side main relay 15 is in a conductive state, and if they do not match, the negative-side main relay 15 is in an open (cut-off) state. It is judged that. Thereby, the microcomputer 2 can detect the state of the negative-side main relay 15. Based on the states of the positive-side main relay 12 and the negative-side main relay 15 thus detected, the microcomputer 2 can diagnose whether these relays are operating normally and perform relay monitoring control. The time required for the microcomputer 2 to switch the measurement of the first to third voltages is determined according to the input channel switching time of the microcomputer 2 and is generally about several μs. Therefore, by performing the measurement of the first voltage and the measurement of the second voltage or the third voltage in synchronization as described above, the microcomputer 2 can perform these voltage measurements almost simultaneously without a time lag. it can.

  Bias resistors 21 are connected to the input sides of the interface circuits 22B and 22C, respectively. When the positive side main relay 12 or the negative side main relay 15 is opened, the charge charged in the X capacitor 17 is discharged via the bias resistor 21. Thereby, a significant potential difference can be generated between the first voltage and the second voltage or the third voltage. Therefore, by measuring these voltages with the microcomputer 2, it can be reliably detected that the positive-side main relay 12 or the negative-side main relay 15 is in the open state.

  Next, the control sequence and expected operation value of the microcomputer 2 in the relay monitoring control will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram showing an example of a normal control sequence and expected operation value according to the first embodiment of the present invention, and FIG. 5 is a control sequence and operation at the time of abnormality according to the first embodiment of the present invention. It is a figure which shows the example of an expected value.

  4 and 5, a timing chart is shown in the upper part of the drawing, and a determination table is shown in the lower part of the drawing. In the upper timing chart, the control timing of each relay and the measurement timing of the first to third voltages are illustrated as an example of the control sequence of the microcomputer 2. Moreover, the state of the change of the voltage between the terminals of the X capacitor 17 and the first to third voltages is illustrated. On the other hand, in the determination table on the lower side, as examples of expected operation values of the microcomputer 2, the measured values of the first to third voltages, and the positive-side main relay 12 and the negative-side main relay 15 obtained from these measured values. The state determination result is illustrated. Note that each section of the timing chart indicated by a broken line in the figure corresponds to each of sections 1 to 6 of the determination table in FIG. 4, and corresponds to each of sections 1 to 7 of the determination table in FIG. In FIGS. 4 and 5, “total voltage”, “positive side relay voltage”, and “negative side relay voltage” represent the first voltage, the second voltage, and the third voltage, respectively.

  As shown in FIGS. 4 and 5, the microcomputer 2 performs the measurement of the first voltage every predetermined cycle. In addition, the microcomputer 2 alternately performs the measurement of the second voltage and the third voltage every predetermined period in synchronization with the measurement of the first voltage.

  In FIG. 4, section 1 is a section corresponding to a period when a host system (not shown) driven by the motor 19 is in a stopped state. In this section 1, in the battery system shown in FIG. 1, the positive-side main relay 12, the precharge relay 13, and the negative-side main relay 15 are all open. The first voltage measured by the microcomputer 2 in the section 1 is equal to the total voltage V1 of the assembled battery 11. On the other hand, since the X capacitor 17 is in a discharge state, the second voltage (positive side relay voltage) and the third voltage (negative side relay voltage) are both 0V. That is, the measured values of these relay voltages are smaller than the predetermined threshold value Vth1. Therefore, the microcomputer 2 detects that both the positive-side main relay 12 and the negative-side main relay 15 are open from the difference between the measured value of the relay voltage and the measured value V1 of the first voltage. Can be diagnosed.

  In FIG. 4, sections 2 to 5 are sections corresponding to a series of periods from when the host system is activated until the battery system of FIG. Section 2 corresponds to a period from when the negative main relay 15 is switched to the connected state until the precharge relay 13 is switched to the connected state. In this section 2, the positive-side main relay 12 and the precharge relay 13 remain open. Therefore, similarly to the section 1, the first voltage measured by the microcomputer 2 in the section 2 is the total voltage V1 of the assembled battery 11, and the second voltage is 0V. On the other hand, the negative side main relay 15 is switched from the open state to the connected state. Therefore, in the section 2, the total voltage V1 of the assembled battery 11 is measured as the third voltage. Therefore, since the first voltage and the third voltage match, the microcomputer 2 can detect that the negative main relay 15 is in the connected state and diagnose that it is in the normal state.

  Section 3 corresponds to a period from when the precharge relay 13 is switched to the connected state until the X capacitor 17 is charged. In this section 3, charging of the X capacitor 17 is started when the precharge relay 13 and the negative main relay 15 are connected. Assuming that the second voltage measured in the section 3 is V2, the voltage across the terminals according to the charging state of the X capacitor 17 is measured as the voltage V2, and the total voltage V1 of the assembled battery 11 is measured as the third voltage. Is done. Therefore, the microcomputer 2 detects that the negative side main relay 15 is in a connected state and diagnoses that it is in a normal state since the first voltage and the third voltage match as in the case of the section 2. can do. If the threshold value for the microcomputer 2 to determine whether the X capacitor 17 is precharged is Vth3, V2 <Vth3 in section 3. Therefore, the precharge of the X capacitor 17 is continued.

  Section 4 corresponds to a period from when the X capacitor 17 is charged to when the positive charge main relay 12 is switched to the connected state until the precharge relay 13 is switched to the open state. Assuming that the second voltage measured in the section 4 is V3, the charging of the X capacitor 17 proceeds and the voltage V3 rises and exceeds the threshold value Vth3, so that the microcomputer 2 has completed the precharging of the X capacitor 17 Judge. Then, after switching the positive-side main relay 12 to the connected state, the microcomputer 2 switches the precharge relay 13 to the open state.

  Section 5 corresponds to a period after the precharge relay 13 is switched to the open state. In this section 5, the charging of the X capacitor 17 is completed, and the voltage between the terminals of the X capacitor 17 is equal to the total voltage V <b> 1 of the assembled battery 11. Further, the positive side main relay 12 and the precharge relay 13 are switched to the connected state. Therefore, in the section 5, the total voltage V1 of the assembled battery 11 is measured as the second voltage and the third voltage, respectively. Therefore, the microcomputer 2 detects that the positive side main relay 12 and the negative side main relay 15 are in a connected state because the first voltage, the second voltage, and the third voltage match each other. Can be diagnosed as having a condition.

  In FIG. 4, section 6 corresponds to a period when both positive-side main relay 12 and negative-side main relay 15 are in a normal state after section 5 has elapsed. In the section 6, as in the section 5, the total voltage V1 of the assembled battery 11 is measured as the second voltage and the third voltage, respectively. Therefore, the microcomputer 2 detects that the positive side main relay 12 and the negative side main relay 15 are in a connected state because the first voltage, the second voltage, and the third voltage match each other. Can be diagnosed as having a condition. As a result, the microcomputer 2 can confirm that there is no abnormality in which these relays are unintentionally opened.

  FIG. 5 shows a case where the negative main relay 15 is unintentionally switched to the open state in the section 6 after the same operation as in FIG. 4 is performed in the sections 1 to 5. In this case, when the total voltage V1 of the assembled battery 11 is measured as the second voltage, and the third voltage measured in the section 6 is V4, the terminal voltage corresponding to the charge state of the X capacitor 17 is Measured as voltage V4. When the negative main relay 15 is opened, the charge charged in the X capacitor 17 is discharged through the bias resistor 21 as described above, so that the voltage across the X capacitor 17 gradually decreases. Here, the threshold value for the microcomputer 2 to make the relay open determination is Vth2, and when the difference between the first voltage and the second voltage or the third voltage exceeds the threshold value Vth2, the microcomputer 2 It is determined that the main relay 12 or the negative main relay 15 is in an open state. In section 6, V4> V1-Vth2 because a large amount of charge still remains in the X capacitor 17. Therefore, at this time, it is determined that the negative main relay 15 is in a normal state.

  On the other hand, when the third voltage measured in the section 7 is V5, the discharge of the X capacitor 17 proceeds and the voltage between the terminals decreases, so that V5 <V1-Vth2, and the negative main relay 15 is in the open state. The microcomputer 2 detects this. From the detection result of the state of the negative main relay 15, the microcomputer 2 can determine that the negative main relay 15 has switched to an unintended abnormal open state.

  Through the relay monitoring control as described above, the microcomputer 2 can monitor the states of the positive-side main relay 12 and the negative-side main relay 15 and detect whether or not an abnormality has occurred.

  According to the 1st Embodiment of this invention demonstrated above, there exist the following effects.

(1) The battery monitoring device 23 indicates the states of the positive-side main relay 12 and the negative-side main relay 15 connected between the positive and negative terminals of the assembled battery 11 that is a secondary battery and the inverter 18 that is a load, respectively. A microcomputer 2 that performs voltage measurement for detection, and a high-voltage measurement interface circuit group 22 provided between the microcomputer 2 and the positive-side main relay 12 and the negative-side main relay 15 are provided. The positive main relay 12 conducts or cuts off between the first positive contact provided on the positive terminal side of the assembled battery 11 and the second positive contact provided on the inverter 18 side. The negative main relay 15 conducts or cuts off between the first negative contact provided on the negative terminal side of the battery pack 11 and the second negative contact provided on the inverter 18 side. The microcomputer 2 includes a first voltage between the first positive electrode contact and the first negative electrode contact, a second voltage between the second positive electrode contact and the first negative electrode contact, and a first positive electrode. The third voltage between the contact and the second negative contact can be measured via the high voltage measurement interface circuit group 22, respectively. Further, the microcomputer 2 determines the positive main relay 12 based on the measurement result of the first voltage and the measurement result of the second voltage when the measurement of the first voltage and the measurement of the second voltage are performed in synchronization. Detect the state of. Further, the microcomputer 2 performs the negative main relay 15 based on the first voltage measurement result and the third voltage measurement result when the first voltage measurement and the third voltage measurement are performed in synchronization. Detect the state of. Since it did in this way, the state of the positive electrode side main relay 12 and the negative electrode side main relay 15 which were each provided in the positive electrode terminal side and the negative electrode terminal side of the assembled battery 11 can be detected correctly.

(2) The battery monitoring device 23 determines the connection state between at least one of the first positive contact, the second positive contact, the first negative contact, and the second negative contact and the high voltage measurement interface circuit group 22. A sensor connection selector switch group 20 for switching is further provided. Specifically, the sensor connection changeover switch group 20 includes a changeover switch 20A2 and a changeover switch 20C2 connected between the first positive electrode contact and the high voltage measurement interface circuit group 22, respectively, and a second positive electrode contact and a high voltage. A changeover switch 20B2 connected between the voltage measurement interface circuit group 22, a changeover switch 20A1 and a changeover switch 20B1 respectively connected between the first negative contact and the high voltage measurement interface circuit group 22, and a second Switch 20 </ b> C <b> 1 connected between the negative contact and the high-voltage measurement interface circuit group 22. The high voltage measurement interface circuit group 22 includes an interface circuit 22A that outputs a first voltage to the microcomputer 2 via the changeover switch 20A2 and the changeover switch 20A1, and a second voltage via the changeover switch 20B2 and the changeover switch 20B1. And an interface circuit 22C for outputting a third voltage to the microcomputer 2 via the changeover switch 20C2 and the changeover switch 20C1. Since it did in this way, in the microcomputer 2, a 1st voltage, a 2nd voltage, and a 3rd voltage can be measured safely and reliably.

-Second Embodiment-
FIG. 2 is a diagram showing a configuration of a battery system including a battery monitoring device according to the second embodiment of the present invention. The battery system shown in FIG. 2 is different from the battery system according to the first embodiment shown in FIG. 1 in that the high voltage measurement interface circuit group 22 includes two interface circuits 22A and 22D.

  In the present embodiment, the interface circuit 22D is used in place of the interface circuits 22B and 22C in FIG. That is, the interface circuit 22D outputs the second voltage to the microcomputer 2 via the changeover switches 20B1 and 20B2. Further, the third voltage is output to the microcomputer 2 via the changeover switches 20C1 and 20C2. The microcomputer 2 can measure the second voltage and the third voltage via the interface circuit 22D. A bias resistor 21 is connected to the input side of the interface circuit 22D.

  According to the second embodiment of the present invention described above, the same operational effects as (1) described in the first embodiment and the following operational effects (3) are achieved.

(3) The battery monitoring device 23 determines the connection state between at least one of the first positive contact, the second positive contact, the first negative contact and the second negative contact and the high voltage measurement interface circuit group 22. A sensor connection selector switch group 20 for switching is further provided. Specifically, the sensor connection changeover switch group 20 includes a changeover switch 20A2 and a changeover switch 20C2 connected between the first positive electrode contact and the high voltage measurement interface circuit group 22, respectively, and a second positive electrode contact and a high voltage. A changeover switch 20B2 connected between the voltage measurement interface circuit group 22, a changeover switch 20A1 and a changeover switch 20B1 respectively connected between the first negative contact and the high voltage measurement interface circuit group 22, and a second Switch 20 </ b> C <b> 1 connected between the negative contact and the high-voltage measurement interface circuit group 22. The high voltage measurement interface circuit group 22 includes an interface circuit 22A that outputs a first voltage to the microcomputer 2 via the changeover switch 20A2 and the changeover switch 20A1, and a second voltage via the changeover switch 20B2 and the changeover switch 20B1. And an interface circuit 22D that outputs a third voltage to the microcomputer 2 via the changeover switch 20C2 and the changeover switch 20C1. Since it did in this way, in the microcomputer 2, a 1st voltage, a 2nd voltage, and a 3rd voltage can be measured safely and reliably. Furthermore, compared with the first embodiment, the circuit scale of the high voltage measurement interface circuit group 22 can be reduced, and the number of parts can be reduced.

-Third embodiment-
FIG. 3 is a diagram showing a configuration of a battery system including a battery monitoring apparatus according to the third embodiment of the present invention. The battery system shown in FIG. 3 is different from the battery system according to the first embodiment shown in FIG. 1 in that the high voltage measurement interface circuit group 22 includes an A / D converter 24 and three interface circuits 22E, 22F, and 22G. The sensor connection changeover switch group 20 is constituted by only three changeover switches 20A2, 20B2, and 20C2. The battery monitoring device 23 is further different from the battery system according to the first embodiment in that the battery monitoring device 23 further includes an insulated power supply 25, an insulated communication element 26, and an LDO (low dropout linear regulator) 27.

  The interface circuit 22E converts the first voltage input through the changeover switch 20A2 into a voltage within the input voltage range of the A / D converter 24, and outputs the voltage to the A / D converter 24. The interface circuit 22F converts the second voltage input via the changeover switch 20B2 into a voltage within the input voltage range of the A / D converter 24 and outputs the voltage to the A / D converter 24. The interface circuit 22G converts the third voltage input via the changeover switch 20C2 into a voltage within the input voltage range of the A / D converter 24, and outputs the voltage to the A / D converter 24. The A / D converter 24 converts the input first to third voltages into digital values, respectively, and outputs the digital values to the microcomputer 2 via the insulating communication element 26. The microcomputer 2 can measure the first to third voltages by acquiring the digital values of the first to third voltages from the A / D converter 24, respectively.

  The insulated power source 25 supplies the LDO 27 with the power source insulated from the power source IC 1 based on the power source supplied from the power source IC 1. The LDO 27 generates an operation power supply for the A / D converter 24 based on the power supplied from the insulated power supply 25 and supplies the operation power to the A / D converter 24.

  In the battery system of FIG. 3, the insulation between the high voltage measurement interface circuit group 22 and the power supply IC 1 and the microcomputer 2 is ensured by the insulated power supply 25 and the insulated communication element 26. Thereby, even if the input impedance of the high voltage measurement interface circuit group 22 is low, insulation between the high voltage circuit connected to the assembled battery 11 and the low voltage circuit including the microcomputer 2 can be ensured. Therefore, the sensor connection change-over switch group 20 can be configured by only the positive-side change-over switches 20A2, 20B2, and 20C2, and the negative-side change-over switches 20A1, 20B1, and 20C1 shown in FIGS. 1 and 2 can be omitted. Further, the resistances of the interface circuits 22E, 22F, and 22G can be used as bias resistors, and the bias resistor 21 shown in FIGS. 1 and 2 can be omitted.

  As shown in FIG. 3, the battery system of the present embodiment may be configured such that the branch from the first positive contact to the changeover switches 20 </ b> A <b> 2 and 20 </ b> C <b> 2 is performed inside the battery monitoring device 23. Thereby, the number of connection lines and connector terminals of the battery monitoring device 23 can be reduced, and the structure can be simplified.

  In the battery system according to the present embodiment, the sign of the third voltage is inverted and detected as compared with the battery systems according to the first and second embodiments shown in FIGS. This point will be described below with reference to FIGS. FIG. 6 is a diagram showing an example of a normal control sequence and expected operation value according to the third embodiment of the present invention, and FIG. 7 is a control sequence and operation at the time of abnormality according to the third embodiment of the present invention. It is a figure which shows the example of an expected value.

  Similar to FIGS. 4 and 5, in FIGS. 6 and 7, a timing chart is shown in the upper part of the drawing, and a determination table is shown in the lower part of the drawing. 6 and 7, the upper timing charts are the same as those in FIGS. 4 and 5 except for the state of the third voltage change shown in the lowermost stage. In the lower determination table, the portions other than the measured value of the third voltage are the same as those in FIGS. 4 and 5, respectively.

  In FIG. 6 and FIG. 7, since the X capacitor 17 is in the discharged state in the section 1, the third voltage (negative relay voltage) measured by the microcomputer 2 is equal to the total voltage V <b> 1 of the assembled battery 11. Here, the threshold value for the microcomputer 2 to determine whether the negative main relay 15 is opened is Vth4. When the difference between the first voltage and the third voltage falls below the threshold value Vth4, the microcomputer 2 It is determined that the main relay 15 is in an open state. In section 1, since both the first voltage and the third voltage are equal to V1, it is possible to detect that the negative main relay 15 is in the open state and diagnose it as being in a normal state.

  In section 2, since the negative main relay 15 is switched from the open state to the connected state, the measured value of the third voltage is 0 V, which is smaller than the aforementioned threshold value Vth1. That is, the difference between the first voltage and the third voltage is smaller than the threshold value Vth4. Therefore, the microcomputer 2 can detect that the negative-side main relay 15 is in a connected state and diagnose that it is in a normal state.

  In the case of FIG. 6, since the negative side main relay 15 remains in the connected state after the section 2, the operation and determination similar to those in the section 2 are performed by the microcomputer 2 in the sections 3 to 6. On the other hand, in the case of FIG. 7, the negative side main relay 15 is unintentionally switched to the open state in the section 6. Therefore, the third voltage V4 measured in the section 6 is equal to a voltage obtained by subtracting the inter-terminal voltage corresponding to the charged state of the X capacitor 17 from the total voltage V1 of the assembled battery 11. When the negative main relay 15 is opened, the charge charged in the X capacitor 17 is discharged through the interface circuit 22G, so that the voltage between the terminals of the X capacitor 17 gradually decreases. In section 6, since a large amount of charge still remains in the X capacitor 17, V4 <V1-Vth4 although V4> Vth1. Therefore, at this time, it is determined that the negative main relay 15 is in a normal state.

  Thereafter, as the discharge of the X capacitor 17 proceeds and the voltage between the terminals decreases, the third voltage increases, and in the third voltage V5 measured in the section 7, V5> V1−Vth4. Thereby, the microcomputer 2 detects that the negative side main relay 15 is in an open state. From the detection result of the state of the negative main relay 15, the microcomputer 2 can determine that the negative main relay 15 has switched to an unintended abnormal open state.

  According to the third embodiment of the present invention described above, the same operational effects as (1) described in the first embodiment and the following (4) operational effects are exhibited.

(4) The battery monitoring device 23 determines the connection state between at least one of the first positive contact, the second positive contact, the first negative contact, and the second negative contact and the high voltage measurement interface circuit group 22. A sensor connection selector switch group 20 for switching is further provided. Specifically, the sensor connection changeover switch group 20 includes a changeover switch 20A2 and a changeover switch 20C2 connected between the first positive electrode contact and the high voltage measurement interface circuit group 22, respectively, and a second positive electrode contact and a high voltage. And a changeover switch 20B2 connected to the voltage measurement interface circuit group 22. The high voltage measurement interface circuit group 22 includes an A / D converter 24, an interface circuit 22E that outputs the first voltage to the A / D converter 24 via the changeover switch 20A2, and a second voltage via the changeover switch 20B2. The interface circuit 22F that outputs the voltage of 2 to the A / D converter 24 and the interface circuit 22G that outputs the third voltage to the A / D converter 24 via the changeover switch 20C2. The A / D converter 24 converts the first voltage, the second voltage, and the third voltage into digital values and outputs the digital values to the microcomputer 2. Since it did in this way, in the microcomputer 2, a 1st voltage, a 2nd voltage, and a 3rd voltage can be measured safely and reliably. Furthermore, as compared with the first embodiment, the number of changeover switches constituting the sensor connection changeover switch group 20 can be reduced and the bias resistor 21 can be omitted to reduce the number of parts.

  Each embodiment and modification described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired.

1: Power supply IC
2: Microcomputer 3: Communication interface circuit 4A, 4B: Insulation communication element 5: Cell voltage monitoring IC
7: Relay control unit 8: Current sensor interface circuit 9: Current sensor 10: Battery cell 11: Battery pack 12: Positive side main relay 13: Precharge relay 14: Precharge resistor 15: Negative side main relay 16A, 16B: Y Capacitor 17: X capacitor 18: Inverter 19: Motor 20: Sensor connection changeover switch group 21: Bias resistor 22: High voltage measurement interface circuit group 23: Battery monitoring device 24: A / D converter 25: Insulated power supply 26: Insulated communication element 27: LDO

Claims (5)

A voltage measurement circuit that performs voltage measurement for detecting the state of the positive side relay and the negative side relay connected between the positive electrode terminal and the negative electrode terminal of the secondary battery and the load, and
An interface circuit group provided between the voltage measurement circuit and the positive-side relay and the negative-side relay, and
The positive side relay conducts or cuts off between a first positive contact provided on the positive terminal side of the secondary battery and a second positive contact provided on the load side,
The negative electrode side relay conducts or cuts off between a first negative electrode contact provided on the negative electrode terminal side of the secondary battery and a second negative electrode contact provided on the load side,
The voltage measurement circuit includes:
A first voltage between the first positive contact and the first negative contact; a second voltage between the second positive contact and the first negative contact; A third voltage between the positive electrode contact and the second negative electrode contact can be measured via the interface circuit group;
The state of the positive-side relay based on the measurement result of the first voltage and the measurement result of the second voltage when the measurement of the first voltage and the measurement of the second voltage are performed in synchronization. Detect
Based on the measurement result of the first voltage and the measurement result of the third voltage when the measurement of the first voltage and the measurement of the third voltage are performed in synchronization, the state of the negative-side relay Battery monitoring device to detect. The battery monitoring device according to claim 1,
A selector switch group for switching a connection state between at least one of the first positive contact, the second positive contact, the first negative contact, and the second negative contact and the interface circuit group; Battery monitoring device provided. The battery monitoring device according to claim 2,
The changeover switch group includes a first changeover switch and a second changeover switch connected between the first positive electrode contact and the interface circuit group, the second positive electrode contact, and the interface circuit group, respectively. A third changeover switch connected between the first negative electrode contact and the interface circuit group, a fourth changeover switch and a fifth changeover switch, respectively, and the second negative electrode. A sixth changeover switch connected between the contact point and the interface circuit group,
The interface circuit group includes a first interface circuit that outputs the first voltage to the voltage measurement circuit via the first changeover switch and the fourth changeover switch, the third changeover switch, and the third changeover switch. A second interface circuit that outputs the second voltage to the voltage measurement circuit via a fifth changeover switch; and the third voltage via the second changeover switch and the sixth changeover switch. And a third interface circuit for outputting to the voltage measuring circuit. The battery monitoring device according to claim 2,
The changeover switch group includes a first changeover switch and a second changeover switch connected between the first positive electrode contact and the interface circuit group, the second positive electrode contact, and the interface circuit group, respectively. A third changeover switch connected between the first negative electrode contact and the interface circuit group, a fourth changeover switch and a fifth changeover switch, respectively, and the second negative electrode. A sixth changeover switch connected between the contact point and the interface circuit group,
The interface circuit group includes a first interface circuit that outputs the first voltage to the voltage measurement circuit via the first changeover switch and the fourth changeover switch, the third changeover switch, and the third changeover switch. The second voltage is output to the voltage measurement circuit via a fifth changeover switch, and the third voltage is supplied to the voltage measurement circuit via the second changeover switch and the sixth changeover switch. A battery monitoring device including a fourth interface circuit for outputting. The battery monitoring device according to claim 2,
The changeover switch group includes a first changeover switch and a second changeover switch connected between the first positive electrode contact and the interface circuit group, the second positive electrode contact, and the interface circuit group, respectively. A third changeover switch connected between
The interface circuit group includes an A / D converter, a fifth interface circuit that outputs the first voltage to the A / D converter via the first changeover switch, and a third changeover switch. A sixth interface circuit for outputting the second voltage to the A / D converter, and a seventh interface circuit for outputting the third voltage to the A / D converter via the second changeover switch. And including
The A / D converter is a battery monitoring apparatus that converts the first voltage, the second voltage, and the third voltage into digital values and outputs the digital values to the voltage measurement circuit.

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